1. Field of Invention
The present invention relates generally to a positioning device for use in a backrest of a stroller which is adjustable in the angle of elevation and, more particularly, is well designed for undertaking additional torsion imposed on it and maintaining the predetermined position.
2. Related Art
A stroller is normally composed of a front frame, a rear frame, a handrail frame, a seat frame and a backrest. The conventional frames of a stroller are structured to have a foldable mechanism for convenience of carrying out and for the reduction of occupied space. Wheels are connected to the front and rear frames for easy moving. Soft pads are put on the seat frame and the backrest for more comfortable seating. The backrest of the stroller is generally one of two types, fixed or adjustable. The backrest in the fixed type is fixed on the seat frame and has only one declining angle after being assembled, while the adjustable type is pivoted on the seat frame and is adjustable in the declining angle. The angle between the seat frame and the backrest can be 180 degrees, that is, the backrest is in the same smooth plane with the seat frame for the baby to lie down, or 100 or 120 degrees for different lying posture. The point is that the adjustable backrest is always fixed to support the baby when it is moved to the desired position.
As taught in the U.S. Pat. No. 5,482,311, which disclosed a backrest adjusting device for a stroller which includes a slidable seat slidably mounted to each of the two limbs of a backrest frame member of the stroller. Each slidable seat includes a receptacle, a spring mounted in the receptacle, a first pin mounted above the spring and transversely passing through an associated limb of the backrest frame member, a stop piece mounted in the receptacle and located above the first pin thereby defining a lowermost position of the slidable seat, and s second pin projecting outward from an outer periphery thereof. A pull bar is mounted between the slidable seats. The second pin engage with sockets defined in a frame of the stroller when the backrest frame member is in a substantially upright position. The backrest frame member is pivotable to a substantially horizontal position when the second pin disengage from the socket upon actuation of the pull bar which causes upward movement of the slidable seats.
U.S. Pat. No. 5,447,323 disclosed another positioning device of backrest of a stroller which comprises a positioning plate securely mounted to each of two limbs of the backrest frame member of the stroller and has a pushing piece extending toward a front direction of the stroller and a flexible operative piece having a recess therein which faces the front direction of the stroller. The stroller has a pair of mounting seats for mounting the canopy frame member and the rear members thereof to the handle thereof. Each mounting seat has a peg thereon for releasably engaging with the recess of the associated flexible operative piece.
All the above-mentioned patents belong to the kind of positioning devices for a backrest of a stroller which have to do with the loading of a child imposed thereon when sitting on the stroller. They employ hooking devices which engage with the accompanying pegs downward or upward to complete the positioning action.
However, whatever positioning devices are used, they must be capable of firmly holding the position set and secure the child sitting thereon. In the case of aforesaid unsteadily vibration, the child makes not only a downward gravity force but also a lateral or tortional force. This will cause the positioning device to move from its predetermined position and cause the backrest to suddenly fall down, which can, in turn, injure the child.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results could be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and detailed description of the preferred embodiment in addition to the scope of the invention as defined by the claims taken in conjunction with the accompanying drawings.
Accordingly, the present invention provides mainly a positioning device for use in a backrest of a stroller which securely maintains the intended position.
In order to meet the object of the present invention, which comprises: a positioning seat mounted on the rear frame and a wedging hook mounted on the backrest for engaging with the positioning seat. A safe end is equipped on the positioning seat for securely maintaining the position between the wedging hook and the positioning seat to make the backrest firmly keep its position when an accidentally torsion force occurs.
These and other features of the present invention will become more fully apparent from the following description and dependent claims taken in conjunction with the accompanying drawings.